Studies in the area of microbial ecology have involved the introduction of selected bacteria or antibiotics in particular environments: intestinal tract, farm, laboratory, and home.

Early studies showed the effect of the introduction of low levels of antibiotics as growth promoters in chickens on antibiotic resistance among bacteria in animals and people on a farm. Other studies showed spread of resistant bacteria and resistance plasmids among bacteria in man and animals.

Other work has looked at the survival of bacteria under different conditions, as well as the transfer of plasmids within the gastrointestinal tract. Studies have looked at the kinds of resistance determinants in wild animals and fish and the spread of resistant bacteria on the farm environment.

Some of the more epidemiologic studies have looked at the role of antibiotics in the selection of drug resistant strains.

Home Environments and Biocides
The microbiology of the home environment is receiving new attention, particularly in the wake of food-borne diseases and the potential consequences of increasing numbers of household products bearing antibacterial chemicals. The latter include triclosan, triclocarbon and quaternium ammonium compounds. We have demonstrated that triclosan, like other antibiotics, has a target, the enoyl reductase, involved in lipid biosynthesis. Mutations in the gene fabI leads to triclosan resistance. Resistance to this and other biocides can also be linked to multidrug efflux pumps such as AcrAB in E. coli which mediate cross resistance to antibiotics.

With the mounting number of biocide-containing products entering the market for household use, there is heightened concern that they will contribute to the rising problem of antibiotic resistance among bacteria. Studies in this area look at the mechanism of action, mechanism of resistance and epidemiology of biocide/antibiotic resistant organisms in the home. Other studies focus on household practices relating to hygiene so as to better understand the interaction between hygiene, infection and the “hygiene hypothesis,” namely the effect of overzealous hygienic measures on emergence of allergic disorders, such as asthma and dermatitis.